The present invention relates to a washing apparatus for a fluidized bed pelletizing and drying machine, capable of simultaneously washing a bag filter and the inner surface of the body of the fluidized bed pelletizing and drying machine.
As shown in FIG. 7, solid particles 65 stacked on a sintered metal net unit 64 installed at the lower end of a product container 63 are sprayed with a binder liquid or coating liquid from a nozzle 66 for pelletization or coating while they are fluidized by a fluidizing gas 62 introduced from the bottom section 61 of a fluidized bed pelletizing and drying machine 60 which is closed.
The gas 67 used for fluidization moves up in the body 69 as a gas containing fine solid particles. After having its solid particles removed by a bag filter 70 disposed in the upper region, the gas is discharged as the spent gas 72 from an exhaust duct 71. The bag filter 70 comprises a filter body 68 in the form of a bowl turned bottom upward, filter elements 73 projecting in the form of bottomed socks and disposed in concentric circles in the filter body 68, and a substantially cylindrical skirt portion 74 downwardly extending from the filter body 68. During treatment of powder particles, the bag filter is kept hoisted to the upper region of the body 69 by a wire 76 connected to a winch 75. Further, during treatment of powder particles, a seal tube 77 mounted on the inner surface of the body 69 closely contacts the skirt portion 74. Therefore, the bag filter 70 is held in the sealed state in the body 69 during said treatment.
When it is desired to wash the fluidized bed pelletizing and washing machine 60 first, the product container 63 and nozzle 66 are removed and then the fluid is discharged from the seal tube 77 to allow the bag filter 70 collapse. Subsequently, lowering and raising means 75 is driven to lower the bag filter 70, whereupon the latter is taken out and inner surface of the body 69 and the bag filter 70 are separately washed. However, with such washing method used, the bag filter 70 has to be taken outside the body 69, a fact which means that dust of particles stuck to the inner and outer surfaces of the bag filter 70 is scattered outside the body, and since the body 68 and the bag filter 70 are separately washed, the washing load is high, decreasing the washing efficiency. Further, since the removal of the bag filter has to be manually effected, full automation of washing operation is difficult to realize.
To solve such problem, for example, a washing apparatus as shown in Japanese Utility Model Application No. 62395/1984 is suggested. This washing apparatus, as shown in FIG. 8, is constructed by adding the following technical means to the washing apparatus described above: Upper and lower washing water spouting nozzles 78 and 79 are disposed above and below a vertically movable bag filter 70. The upper nozzle 78 is vertically movable by lifting means 80, while the lower nozzle 79 is fixed below a sintered metal net unit 64.
In the washing apparatus of such arrangement, upon completion of the treatment of powder particles, the bag filter 70 is lowered until it is close to the lower nozzle 79, while the upper nozzle 78 is lowered until it is close to the upper surface of the bag filter 70 now lowered. Then, washing water is spouted from the upper and lower nozzles 78 and 79 to wash the bag filter 70 and the inner surface of the body 69.
Such washing operation makes it possible to simultaneously wash the bag filter 70 and the inner surface of the body 69 without removing the bag filter 70 from inside the body 69. Therefore, there is no possibility of dust being scattered during the washing of the bag filter 70, and the washing load is light, increasing the washing efficiency. Further, by making the lifting means for the bag filter 70 and upper nozzle 78 in the form of an automatic lifting device and automatically controlling the supply of washing water to the upper and lower nozzles 78 and 79, it becomes possible to completely automate the washing operation on the bag filter 70 and the inner surface of the body 69; this will also enhance automation of the factory.
The washing apparatus described in Japanese Utility Model Application No. 62395 mentioned above has the following problems.
(1) Since the range of washing water spouting from the upper and lower nozzles is limited, it is difficult to uniformly wash every area. Further, the washing liquid hardly reach the inner surface of the filter elements in the form of bottomed socks; thus, the washing is liable to be insufficient. PA1 (2) Since the upper nozzle is in the lowered position during washing, the washing of the inner surface of the portion of the body above the upper nozzle is insufficient. PA1 (3) Since the lower nozzle is disposed below the sintered metal net unit, the washing liquid spouted from the lower nozzle reaches the areas to be washed only after it passes through the sintered metal net unit. This means that the washing water pressure at the areas to be washed is decreased and hence the washing of the inner surface of the body and the inner surface of the bag filter effected by the lower nozzle is insufficient. In addition, if the sintered metal net unit is removed prior to washing, such problem can be solved. In this case, however, attachment and detachment of the sintered metal net unit have to be manually effected, making it difficult to completely automate the washing operation. PA1 said washing apparatus being characterized in that the washing apparatus comprises an upright three-dimensional rotary nozzle unit capable of vertically moving in a space above said bag filter, a horizontal three-dimensional rotary nozzle unit capable of horizontally advancing and retracting between a position in the body below the uppermost position of the bag filter and a position outside the body, and a washing container in which is disposed a multiple two-dimensional horizontal rotary nozzle unit adapted to spout washing liquid from below toward the inner surface of the bag filter,
The present invention, accomplished with the above in mind, is intended to provide a washing apparatus for a fluidized bed pelletizing and drying machine which is capable of simultaneously washing the bag filter and the inner surface of the body without removing the bag filter from inside the body, achieving complete automation of the washing operation and which solves the problems (1) through (3) described above so as to ensure reliable washing of areas to be washed.